飞秒激光作用下透明介质材料的反射率演化  

Time-Resolved Reflectivity Evolution of Transparent Dielectrics under Femtosecond-Laser Pulse Excitation

作　　者：徐世珍[1] 贾天卿[1] 孙海轶[1] 李晓溪[1] 冯东海[1] 李成斌[1] 王晓峰[1] 邱建荣[1] 徐至展[1] 

机构地区：[1]中国科学院上海光学精密机械研究所强场激光物理国家重点实验室,上海201800

出　　处：《中国激光》2006年第1期53-56,共4页Chinese Journal of Lasers

基　　金：国家自然科学基金(60108002)资助项目

摘　　要：利用800 nm抽运和400 nm探针技术,测量了CaF2和MgO的时间分辨反射率,研究了材料的电子激发和弛豫超快动力学过程。采用耦合动力学模型,探讨了飞秒激光对透明介质材料的激发,以及材料的激发对抽运激光在材料中的传输、分布和反射特性的影响。根据这个理论模型计算了时间分辨反射率的演化,计算结果和实验结果相吻合。研究表明,多光子电离(MPI)和碰撞电离(II)在介质材料的导带电子激发中起着重要的作用。Using the 800-nm-pump and 400-nm-probe technique, the dynamics of the electron excitation and relaxation in CaF2 and MgO crystals was studied. A coupling model including both the multiphoton iotization （MPI） and the impact ionization （II） was applied to investigate laser propagation and conduction band electron production. The evolution of refleetivity was calculated, and the calculated results agree with the experimental results. The results indicate that both MPI and II play important roles in the generation of conduction band electrons. The relaxation dynamics was also discussed.

关 键 词：超快光学 飞秒激光 超快动力学 时间分辨反射率 介质材料 

分 类 号：O434.14[机械工程—光学工程] TN248.1[理学—光学]